1*> \brief \b DLCTES 2* 3* =========== DOCUMENTATION =========== 4* 5* Online html documentation available at 6* http://www.netlib.org/lapack/explore-html/ 7* 8* Definition: 9* =========== 10* 11* LOGICAL FUNCTION DLCTES( ZR, ZI, D ) 12* 13* .. Scalar Arguments .. 14* DOUBLE PRECISION D, ZI, ZR 15* .. 16* 17* 18*> \par Purpose: 19* ============= 20*> 21*> \verbatim 22*> 23*> DLCTES returns .TRUE. if the eigenvalue (ZR/D) + sqrt(-1)*(ZI/D) 24*> is to be selected (specifically, in this subroutine, if the real 25*> part of the eigenvalue is negative), and otherwise it returns 26*> .FALSE.. 27*> 28*> It is used by the test routine DDRGES to test whether the driver 29*> routine DGGES successfully sorts eigenvalues. 30*> \endverbatim 31* 32* Arguments: 33* ========== 34* 35*> \param[in] ZR 36*> \verbatim 37*> ZR is DOUBLE PRECISION 38*> The numerator of the real part of a complex eigenvalue 39*> (ZR/D) + i*(ZI/D). 40*> \endverbatim 41*> 42*> \param[in] ZI 43*> \verbatim 44*> ZI is DOUBLE PRECISION 45*> The numerator of the imaginary part of a complex eigenvalue 46*> (ZR/D) + i*(ZI). 47*> \endverbatim 48*> 49*> \param[in] D 50*> \verbatim 51*> D is DOUBLE PRECISION 52*> The denominator part of a complex eigenvalue 53*> (ZR/D) + i*(ZI/D). 54*> \endverbatim 55* 56* Authors: 57* ======== 58* 59*> \author Univ. of Tennessee 60*> \author Univ. of California Berkeley 61*> \author Univ. of Colorado Denver 62*> \author NAG Ltd. 63* 64*> \ingroup double_eig 65* 66* ===================================================================== 67 LOGICAL FUNCTION DLCTES( ZR, ZI, D ) 68* 69* -- LAPACK test routine -- 70* -- LAPACK is a software package provided by Univ. of Tennessee, -- 71* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 72* 73* .. Scalar Arguments .. 74 DOUBLE PRECISION D, ZI, ZR 75* .. 76* 77* ===================================================================== 78* 79* .. Parameters .. 80 DOUBLE PRECISION ZERO, ONE 81 PARAMETER ( ZERO = 0.0D+0, ONE = 1.0D+0 ) 82* .. 83* .. Intrinsic Functions .. 84 INTRINSIC SIGN 85* .. 86* .. Executable Statements .. 87* 88 IF( D.EQ.ZERO ) THEN 89 DLCTES = ( ZR.LT.ZERO ) 90 ELSE 91 DLCTES = ( SIGN( ONE, ZR ).NE.SIGN( ONE, D ) ) 92 END IF 93* 94 RETURN 95* 96* End of DLCTES 97* 98 END 99